Christiane Montastier

A full-UV spectrum absorbing daily use cream protects human skin against biological changes occurring in photoaging

Background: There is overwhelming evidence that exposure of human skin to ultraviolet radiations (UVR) leads to the development of cutaneous photoaging and eventually to neoplasia. This study was designed to evaluate in humans the protection afforded by a daily use cream containing a photostable combination of UVB and UVA absorbers (Uvinul® N539, Parsol® 1789 and Mexoryl® SX) providing a continuous absorption through the entire UV spectrum, against damages induced by repeated daily exposure to solar simulated radiation (SSR).

Clinical evidence of benefits of a dietary supplement containing probiotic and carotenoids on ultraviolet‐induced skin damage

Background  Lactobacillus johnsonii (La1) has been reported to protect skin immune system homeostasis following ultraviolet (UV) exposure.

Changes in matrix gene and protein expressions after single or repeated exposure to one minimal erythemal dose of solar-simulated radiation in human skin in vivo

Abstract Damage to the skin extracellular matrix (ECM) is the hallmark of long-term exposure to solar UV radiation. The aim of our study was to investigate the changes induced in unexposed human skin in vivo after single or repeated (five times a week for 6 weeks) exposure to 1 minimal erythemal dose (MED) of UV solar-simulated radiation. Morphological and biochemical analyses were used to evaluate the structural ECM components and the balance between the degrading enzymes and their physiologic inhibitors. A three-fold increase in matrix metalloproteinase 2 messenger RNA (mRNA) (P < 0.02, unexposed versus exposed) was observed after both single and repeated exposures. Fibrillin 1 mRNA level was increased by chronic exposure (P < 0.02) and unaltered by a single MED. On the contrary, a single MED significantly enhanced mRNA levels of interleukin-1α (IL-1α), IL-1β (P < 0.02) and plasminogen activator inhibitor-1 (P < 0.05). Immunohistochemistry demonstrated a significant decrease in Type-I procollagen localized just below the dermal–epidermal junction in both types of exposed sites. At the same location, the immunodetected tenascin was significantly enhanced, whereas a slight increase in Type-III procollagen deposits was also observed in chronically exposed areas. Although we were unable to observe any change in elastic fibers in chronically exposed buttock skin, a significant increase in lysozyme and alpha-1 antitrypsin deposits on these fibers was observed. These results demonstrate the existence of a differential regulation, after chronic exposure compared with an acute one, of some ECM components and inflammatory mediators.

Neurogenic modifications induced by substance P in an organ culture of human skin.

Neurogenic inflammation of the skin observed after topical application of an irritant substance or environmental stimulation induces vascular changes and the production of inflammatory mediators. Substance P (SP) is one of the main neuropeptides which trigger an inflammatory response in the skin. So, with the aim to develop an alternative method to study neurogenic inflammation of the skin, we used an organ culture of human skin. SP was added onto epidermis or directly to culture medium in an attempt to reproduce ex vivo the effects described in vivo. Even disconnected from systemic blood circulation, in skin fragments in culture, we observed dose-dependent edema, vasodilation and extravasation of lymphocytes and mast cells through the microvascular wall. Moreover, the release of proinflammatory mediators interleukin 1α and tumor necrosis factor α was evidenced.

Dynamics of skin barrier repair following preconditioning by a biotechnology-driven extract from samphire (Crithmum maritimum) stem cells

Background  With aging, the barrier repair kinetics following any weakening of the epidermal permeability barrier function is commonly slowed down.

Histometric Assessment of the Age-Related Skin Response to 2-Hydroxy-5-Octanoyl Benzoic Acid

Only a handful of topical products have been shown to limit or improve age-related skin damage. 2-Hydroxy-5-octanoyl benzoic acid, also designated β-lipohydroxyacid (β-LHA), is among the active molecules claiming such effects. The present randomized placebo-controlled double-blind study was undertaken to evaluate the effects of β-LHA in young and older women. Both groups responded to the β-LHA-containing formulation, although to different degrees according to age and the biologic parameter considered. Topically applied 1% β-LHA formulation was associated with several changes, the most conspicuous ones being epidermal thickening and dendrocytic hyperplasia. The constellation of biologic modifications remained within physiological limits, close to the characteristics of young skin. It is inferred that topical β-LHA can cause a significant improvement in some epidermal and dermal manifestations of ageing.